setLayoutParams不起作用第二次 [英] setLayoutParams doesn't work second time

问题描述

我写了下面的code先增加的ImageView的大小，并在100ms后降低相同的ImageView的大小。然而，这code增加的ImageView的大小，但它不会降低它的大小或之后100ms的延迟code不影响ImageView的尺寸。

I have written the following code to first increase the size of ImageView and after 100ms decrease the size of the same ImageView. However this code increases the size of ImageView but it doesn't decrease it's size or the code after 100ms delay doesn't affect the imageView dimensions.

我在做什么错了？

uiHandler.post(new Runnable()
{
    @Override
    public void run()
    {
        FrameLayout.LayoutParams layout = (android.widget.FrameLayout.LayoutParams) imageView.getLayoutParams();
        layout.height = (int) (2*iconsSizeInDP);
        layout.width = (int) (2*iconsSizeInDP);
        imageView.setLayoutParams(layout);
        try
        {
            Thread.sleep(50);
        }
        catch (InterruptedException e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        Toast.makeText(getApplicationContext(), "Hello", Toast.LENGTH_SHORT).show();
        // following code block doesnt'affect imageView dimensions
        layout.height = (int) iconsSizeInDP;
        layout.width = (int) iconsSizeInDP;
        imageView.setLayoutParams(layout);
    }
});

问候

推荐答案

您更改布局2倍，在相同的用户界面线程，因此只有最后更改生效。
你应该分开，2 UI线程，就像这样：

You change the layout 2 times in the same UI thread, so only the last change can take effect. You should separate to 2 UI thread, like this:

uiHandler.post(new Runnable()
{
    @Override
    public void run()
    {
        FrameLayout.LayoutParams layout = (android.widget.FrameLayout.LayoutParams) imageView.getLayoutParams();
        layout.height = (int) (2*iconsSizeInDP);
        layout.width = (int) (2*iconsSizeInDP);
        imageView.setLayoutParams(layout);
    }
};
uiHandler.postDelayed(new Runnable()
{
    @Override
    public void run()
    {
        Toast.makeText(getApplicationContext(), "Hello", Toast.LENGTH_SHORT).show();
        // following code block doesnt'affect imageView dimensions
        layout.height = (int) iconsSizeInDP;
        layout.width = (int) iconsSizeInDP;
        imageView.setLayoutParams(layout);
    }
},50);

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